error code (-6000,-83) after 2018 update

I have updated from 2017 to 2018 Accounts Prem
I have
Process all pays for the 2017/18 financial year;
Rebuild your Reckon Accounts 2018 Company files
Create a backup of your Reckon Accounts 2018 company files
I have tried logging on to Company 1 and Company 2 and both will not open giving me error code (-6000,-83)
I have opened the 2018 Reckon icon from the desktop and tried to login as per normal procedure so I am not sure what the issue is?
I have opened the required ports 10181 in and out, turned firewall off and tested turned off AV, checked permissions on the file location and all is good.

Check that only ONE of your computers is trying to HOST the file (for sharing via Windows as well as sharing via the QBDBmgr hosting software). That error message is one of the reasons for that combination. Refer to 'file' menu --> Utilities .... to ensure that one machine IS hosting the file, but all others are NOT hosting the centrally stored/accessible QBW DATA (company) file.

Are you saying you only need the ONE computer (be it all at the end of a terminal server session) involved with Reckon Accounts? If so, then you would only need single user and no sharing complexity at all, and my comments would be irrelevent. Just confirm please. The QBW file cannot be controlled (for sharing to others) by more than one HOST computer. One boss - many slaves. But when running single-user on just one PC - all irrelevant, sorry.

So have you added the user QBDataServiceUser27 to the sharing of the folder location where the files are? and given that user full access? and then run the QBDatabaseServerManager and scanned the folder where those files are? then tried the access again? Cheers Linda